使用 MySQLI 处理 SELECT 查询的结果时遇到问题

Question

我正在尝试使用的基本控制结构是使用用户名和电子邮件查询数据库，这两个都是唯一键，如果其中任何一个在数据库中，请让用户知道他们已被占用并且请选择别的东西。我遇到的问题是以可用的形式获取结果数据，然后我可以检查用户提供的数据。

我从 snippit 中删去了准备好的插入语句，以及验证例程，因为它们都工作正常。

DB connection snippit

try {
    if(!($dbc = new mysqli(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME))){      // Creates the $dbc variable object so we can
                                                                           // have a connection to the database.
                                                                           // uses mysqli functions.
    throw new Exception;
    }

}
catch (Exception $e) {
    echo '<p>Could not connect to the database. Please contact the system administrator.</p>';
} 

注册脚本片段

//before this was validation routines, if anything was wrong the script generated something into $reg_errors which is an array.
if(empty($reg_errors))
{
//queries database if there are any matches for username or email from user input.
if($stmt = $dbc->prepare("SELECT `email`, `username` FROM `users` WHERE `email` = ? OR `username` = ?"))
{
    $stmt->bind_param("ss", $e, $u);
    $stmt->execute();
    $stmt->store_result();
    $rows = $stmt->num_rows;                   //gives the number of rows returned from SELECT query. 0 means no dupes, 1 means one record has BOTH email and username, 2 means two different records (one with email, one with username)

 ##THIS IS WHERE I'M RUNNING INTO TROUBLE GETTING THE DATA IN A USABLE FORM##

    $stmt->close();
} else {
    echo "<p>Can't talk to database right now. Try again later, please.</p>";
}

        if($rows==0)            //no dupes of username or email, so let's try and add them into the DB
        {
            //prepared statement for insertion into DB
            //also get's the count of affected rows. 1 means record inserted correctly. 

        //asks DB if a new row was created, and if so, thanks user for 
        //registration on the site & sends an email to their email.
        //if query doesnt work, an error is triggered
        if($count==1) {
            //constructs a thank you note and emails it to the user, using the email they supplied.
            exit(); 
            } else {
                echo "<p>Unable to process your registration at this time. Please try again later..</p>";
            }
    } else {                    // both username and email might be already used in DB, and error msgs are generated for array.
        if($rows==2) {          // this checks to make sure both entries are dupes        
            $reg_errors['email'] = 'This email address has already been registered. If you have forgotten your password, use the link to the right to have your password sent to you.';
            $reg_errors['username'] = 'This username has already been registered. Please try another.';
        } else {                //this checks to see which of the two (email or username) is already in DB if both arent dupes.

            if((__NEED SOMETHING HERE FROM DB QUERY___ == $_POST['email']) && (__NEED SOMETHING HERE FROM DB QUERY___ == $_POST['username'])) {   //both match entries in DB
                $reg_errors['email'] = 'This email address has already been registered. If you have forgotten your password, use the link to the right to have your password sent to you.';
                $reg_errors['username'] = 'This username has already been registered with this email address. If you have forgotten your password, use the link to the right to have your password sent to you.';
            } elseif(__NEED SOMETHING HERE FROM DB QUERY___==$_POST['email']) {        // email match
                    $reg_errors['email'] = 'This email address has already been registered. If you have forgotten your password, use the link to the right to have your password sent to you.';
            } elseif(__NEED SOMETHING HERE FROM DB QUERY___==$_POST['username']) {     // username match
                $reg_errors['username'] = 'This username has already been registered. Please try another one.';
            }
        }       // end of $rows==2 ELSE
    }           // end of $rows == 0 IF

    } else {           // end of empty reg_errors conditional
        //do something if the reg_error array isnt empty..
    }  

我很确定答案在于迭代并使用结果 mysqli 对象中的 meta_data，但是在我把头撞到墙上几天并像疯子一样倒在 mysqli php 手册页上之后，我仍然没有更接近弄清楚我应该做什么。谁能指出我正确的方向？

Answer 1

从注册脚本开始，你有没有尝试过：

if($stmt = $dbc->prepare("SELECT `email`, `username` FROM `users` WHERE `email` = ? OR `username` = ?"))
{
    $stmt->bind_param("ss", $e, $u);
    $stmt->execute();
    $stmt->bind_result($email, $username);
    $rows = $stmt->num_rows;

    //Move Conditionals Up a Little
    if( $rows == 0 ) {    //If No Records are Found

        //Continue Registration
    }
    else if( $rows == 1 ) { //If One Record is Found

        $stmt->fetch();

        //Do Something With $email and $username from DB Here

    }
    else { //If More than One Record is Found

        while( $stmt->fetch() ) {  //Iterate Through Records

            //Do Something With $email and $username from DB Here
        }
    }
}